Loading apparatus and method



1954 F. WEYERHAEUSER LOADING APPARATUS AND METHOD Filed Dec. 1, 1951 fnveizzor Trade/'1 M Wyerkaeaser Patented Feb. 9, 1954 UNITED STATES PATENT OFFICE LOADING APPARATUS AND METHOD Frederick Weyerhaeuser, St. Paul, Minn., assignor to Rock Island Millwork Company, Rock Island, 111., a corporation of Illinois Application December 1, 1951, Serial No. 259,376

11 Claims.

The present invention relates generally to loading methods and apparatus for feeding dry loose granular material onto a carrier base as a uniformly dense homogeneous layer, and in particular it relates to the loading of material which has a wide range of particle sizes in a manner to minimize or prevent fractionation of the component particles.

The invention is applicable to a wide range of materials, but it has particular reference to feeding a mixture which is predominantly wood sawdust or mill waste intoforms for molding to an integrated product such as a board-like panel characterized by uniformity in density and by homogeneity in substance. Hence, the invention will be explained with reference to its application in the field of making panel boards from dry mixtures chiefly of sawdust, and containing a suitable binder ingredient, such as thermosetting synthetic resin-forming powder.

In the field of molding panels from mill waste sawdust characterized by a high content of flourlike fines, as well as by a variable content of coarser sizes, it is important to secure a product withthe same surface texture or characteristics on both sides of the panel, and at inner faces which may be produced by milling or sanding. To illustrate, it is a practice to use as raw material a dry mixture of. unclassified mill waste sawdust with a suitable dry binder content such as thermosetting resin material. This mixture is loaded onto a plate or into a tray on or in which a panel is to be formed by hot-pressing. The mere act of pouring such a dry mixture causes separation of particles by reason of the differential rates of falling under the influence of gravity. In such an undesired pouring step, the fine particles commonly fall faster than the coarser particles. Thus, on pouring such bulk material to form a moldable layer, the bottom of the layer has a surplus of fines and the top of the layer is deficient in fines. Such a poured layer produces a board with faces of different texture, and in the case of a deficiency of content of fines, the top face may readily be proportionately pitted by reason of the absence of fines to fill in the spaces between coarser particles.

The present invention overcomes these undesirable results and provides a method and'means for loading such a separable dry mixture into a moldable layer without inducing separation of fines and coarse particles.

It is a general object of the invention to maintain the mixture to be used in a bulk form and to move it from a supply of such, bodily onto a receiving member on which it is to be. molded, and with a minimum of opportunity for falling and being simultaneously dispersed.

It is a particularobject of the invention to provide a simple apparatus for loading a travelling carrier base to a uniform height with,

material at a uniform density.

It is also an object of the invention continu-.

ously to form a uniformly dense and homogeneously mixed layer of substantially dry granular material of varying particle size onto a moving carrier base by transfer from a hopper-like sup ply thereof in a manner to minimize size separation. 7

. Various other and ancillary object and advantages of the present invention will become apparent from the following description and explanation of the invention as it is set forth with reference to an exemplary device illustrated in the accompanying drawings, in which:

Fig. 1 is a vertical cross-section of a feeding device showing the relationship of the principal parts thereof, including a supply hopper and a rotary device to move material laterally from the. hopper.

Fig. 2 is a view of the apparatus of Fig. 1 looking to the right in Fig. 1 on the line 22.

Fig. 3 represents a continuous belt to be loaded from the hopper of Fig. 1.

Fig. 4 is a partial View showing a modified form of hopper bottom.

Fig. 5 shows a combination of a loading device on the order of Fig. 1 operating in combination with a leveling rotor.

It is to be understood that the invention is not limited to or by the exemplary forms shown in the drawing, or by the description thereof, and that other changes and modifications are contemplated as falling within the scope of the invention as expressed in the appended claims.

In carrying out the invention the material may be loaded into a single tray, or into a series having substantially uniform density and homogeneity as to the distribution of its particle sizes, and additionally, is loaded to a uniform planar level. Where the carrier sheet at the region of loading is perfectly flat and parallel with the intended loaded level, the fill is of uniform depth. Such a loaded fill may be platen-pressed to produce a panel of uniform thickness and density, and of uniform quality from face to face. The height of the loaded level may be varied by mechanical adjustment of the parts, and operation thereof, within certain limits.

Loading at uniform density is of first importance, and in some ways, as later describedpthe final depth on the carrier may be made uniform by other means useful in conjunction with the loader of the present invention.

In Figs. 1 and 2 there is shown a hopper ha-ving a front wall It], rear wall Ill, side walls 12 and i3 and bottom M. The :bottom is provided with .a relatively thin horizontal straight edge l5iover which material is fed outwardly and under which thelcaded material moves away from the loading :zone. The .front wall has a horizontallower edge is located and spaced in the general'region above. straight/edge l5, providing a rectangular lateral opening 18 .for the hopper. lathe-opening i8 is located a horizontal rotor iii-having horizontal mandrel 26 on axis 2] and arcylindrical contour or face defined by the terminal ends of a series of teeth or spikes 2'2 preferably arranged on the mandrel like a plurality of rakes :or combs. The teeth 22 are such in form and arrangement that they plow through the granular material and thereby agitate it when the material is not free to .move, and so that they engage and move the material when its movementis not obstructed. Thus, the rotor breaks-up-and feeds loosened material laterally from the hopper off the bottomifl. The rotor IQ is set :so that its cylindrical face is close to the straight edge 15, thus to feed what may be termed a sheet of the material from the bottom. in a substantially horizontal direction and at.

a velocity determined by the speed of the rotor. With a full hopper the material is thus discharged in the form of a sheet as confined, but never-.

theless. as a loose mass. In the event that loose material may gradually accumulate and cake at the base of the teeth in the rotor, this result may be obviated by providing stationaryteeth so arranged as to project -into the face ofithe rotor 19 at locations to be cleared by the teeth 22 of the rotor. The bottom edge of the :front wall is a convenient location on which to mount a series :of comb-like teeth 23 projecting into the rotor to keep it clear of caked material.

The location horizontally of the straight edge H: with reference to the rotor axis 2| is variable.-

It may be vertically under the axis in which case the discharged material at the edge I5 leaves in a horizontal direction and then tends to fall as a mass. The invention aims to use the force of the horizontal component of the discharging material as a kinetic doctor to level the load being carried. away by the carrier sheet. Therefore, the load being formed is moved in a direction to oppose the material leaving the hopper. Hence, the force exerted for leveling is dependent upon both the velocity of discharge and the velocity of the movement of the carrier base with its load. Deviations from said vertical alinement of the edge and axis 21 are obviously permissible so long as the function to level in operation is not lost. The limits are variable with variation in the speed of the rotor and of the load, as will be readily appreciated. By moving the edge l5 toward the rear wall H from said vertical alinement there is a tendency to introduce and increase the vertical component in the direction of discharge and to tiecrease the horizontal component "used :for leveling. A point will,. therefore, bereached-for given conditions of operation where the edge l5 or any lower portion of the bottom 14 will become amechan-ical doctor, and thus disrupt and disturb the top layer with the possible results of leaving ripples, and "of eiiecting fractionation in thetopmost particles of the fill. The latter results because thelarge particles which project higher than adjacent smaller particles are pushed back in the leveling and thus possibly pushed down into the load with disturbance of uniformity of density and of distribution of particle sizes.

On-thezother handthe edge-l5 may be moved forwardly of the vertical line with the axis :21, without introducing any vertical component, but with loss of effective force in the horizontal component. The result "will be that the material merely .piles up ahead of edge l5, and at the limiting position the load is levelled by the edge it. However, for simplifying the explanation of the present invention, the preferred location bf the edge 15 is chosen .as vertically under the axis 2| of the rotor.

The location of the edge l8 of the front wall in is subject to variation depending upon the character of the material, its tendency'to'fio'w, and hence its normal angle of repose, and also on the'spacingformand arrangement of the the teeth 22, and of the-teeth 23. Material entering the hopper should not flow over the top of axle 28 when the rotoris idle, and hence "it will not do so when the rotor is turning clockwise in Fig. 1 in its normal feeding operation.

The hopper. is so arranged that a carrierbase may move under it in open space below the straight edge 15. The base may bea flat bottom 30 of a tray 3i having end walls 32 and side walls 33, these wa ls being at or-below the level of the fill to beeire'cted, and hence freely lmovable under the hopper. Suitable positioning supports for such a carrier base or may are provided, as exemplified by the parts designated 35 and:35.

.In the case of carrier bases, and especially trays "of sheet steel in-which the fill is hotmolded on a platen press, the repeated heatihg and cooling, andthe handling, eventually'pro duce deviations from a planar form variously called warping, buckling or bulging. When such a non-planar carrier sheet passes under the loader, its levelled load is not of uniform depth even though its density is uniform. To compress such a load to 'a uniform thickness creates non-uniformity of density in the moided panel. For hot-pressing to uniformly dense and thick panels, thefill must be brought to acondition of uniformity in-mas's per unito'f area. This is best accomplished by affecting both uniformity in depth and uniformity in density.

One way toeifect this ultimatei'result is to hold the carrier sheet in a plane as it passes through the loading zone and under the hopper bottom. Fig. 1 wherein a 'magnetic bottom 3% is shown there are located a bank of permanent magnets 38 positioned to provide a planarizing .pl'atform'and functioning to pull or push the passing sections of the magnetic sheet into a plane parallel with the front edge I5 of the hopper bottom. The magnets are preferably spaced and located in the opening of a collecting hopper 39. Where trays are used, the passage of the tail end of a lone tray, that is, one not followed by another tray in contact therewith, permits excess material to fall into the hopper for re-use. Where the carrier sheet is a continuous conveyer, the hopper 39 may be dispensed with.

Fig. 3' is a representation of a section of a continuous conveyer 4i comparable to tray bottom 30. Over its edges may be located vertical stretches 42 and 43v of two other endless belts forming load-retaining walls for the carrier sheet 4|, comparable to tray side walls 33.

Fig. 4 is a modification of the bottombf the hopper. It shows a bottom 45 having an underside 46 upwardly inclined from the discharging lip or edge 41 to remove it from possible contact with the fill when the latter may rise after release of the bottom 30 from magnets 38. The upper face of the bottom 45 is shown with a structure curving into the interior face of the rear wall 48 of the hopper. Magnets 38* are shown as having'less extent in the direction of movement of the carrier, and hence are limited to functioning largely in the loading zone. The straight edge 4'! of the bottom 45 is very thin in order to give full effect in doctoring the fill by the emerging stream of material. This construction gives more latitude in adjusting the relative speeds, and the speeds themselves, of the carrier sheet 30 and of the rotor I9.

Fig. 5 is a modified form in which the magnetic holding means 38 of Fig. 1 may be dispensed with advantageously at "the loading zone. In the absence of the magnetic holds at the loading zone, a magnetic sheet carrier 30 may be unlevel and the fill on it be of various depths on the carrier base even though it may have a level top. Magnets 38 are located to act on the carrier sheet 30 at a location beyond the loading zone, as shown, but under a leveling rotor 50, arranged to spin at a speed sufficiently high to kick oif the particles in the top layer and thereby reduce the depth of fill to a new and lower level overa planarized bottom 30. The leveling rotor 50 is vertically adjustable, as for example, by being rigid with its horizontal axle 5| carried in a swinging frame of which an arm 52 is shown pivoted at 53. The two headed arrow 54 indicates theadjustability of the frame to raise and lower the striking level of the rotor 50. The rotor 50 has a cylindrical face or contour formed by and comprised of spaced striking bars, prefarably arranged as geometrical elements of the cylinder. These are represented as rectangular steel bars or strips 56 circumferentialy disposed in spaced relation around the face of the cylterial in the direction toward the load 59 approaching the leveling rotor. duced in level to the line 60.

The material .removed by the rotor may be This load is re- 'collected by suitable means. When the rotor kicks material in a direction to fall onto the oncoming load, it should be collected when the carrier sheet 30 is a continuous one, but it need not be collected where the carrier sheet is'a.

6. spaced succession of trays. In the latter case, accumulated material drops between trays into a saving hopper 6|. Collection of kicked material 58.may be accomplished by providing a collecting trough in which there is a moving conveyer such as a worm screw or a traveling belt. As shown a trough is formed by vertical wall; 62 and horizontal shelf 63, on which moves a flat stretch 64 of an endless belt. The latter discharges the collected material beyond the con fines of the apparatus illustrated.

The arrangement of Fig. 5 is advantageous in more exactly fixing the final depth of the fill. For molded panels of different thicknesses produced from fills made by the apparatus of Fig. 1, it is necessary to vary the depth of fill by moving the hopper vertically relative to the carrier sheet 30, In large equipment this is clumsy and over-all accuracy is threatened by sagging or warping of .a long span of the hopper bottom I4, and by inequality in the vertical adjustments of one side wall of the hopperrelative to the other. On the other hand the leveling rotor 5i! may be far more accurately positioned over its full length. In using the combination of loader and leveler as shown in Fig. 5, the loading rotor I9 maybe operated in a hopper positioned to over-fill the tray or carrier, and the leveling rotor. 50 may be used to remove the excess.

The successful operation of the present invention depends upon relating certain dimensions and speeds, to secure the desired kinetic doctoring. This is best explained by reference to Fig. 1. The material It is fed from the hopper III over the edge I5, as shown at II. The density of the material I I is substantially the same as -the density of the material carried away by the sheet carrier SEI or tray. Hence, the material may be considered, in terms of units of volume. If the distance from the lower face of mandrel 20 to the edge I5 of the hopper bottom is the same as a uniform depth of fill I2, the speed of the rotor must be (a) just sufiicient to feed out all that is carried away, or (b) the speed must be even greater to feed more than is carried away. In case (a) the conditions require an out-feeding layer in one direction moving at the same linear velocity as the layer carried away as a fill. This is equivalent to bending the out-fed layer (considered as a mass) around the edge I5. The result is no kinetic doctoring. In case (b) the outfed layer moves faster than the tray, with kinetic doctoring, but with a surplus accumulating faster in proportion to the increase of the differential of linear velocity of out-feed over the velocity of fill removal. To'secure the benefit of the speed differential for kinetic doctoring, withaccompanying minimizing of accumulation of surplus, the vertical dimension of the out-feed orifice from the mandrel 20 to the bottom, or the edge I5 in Fig. 1, is made less than the thickness of fill carried away. Thus, the two conditions are the out-feed of a layer of less thickness than the load carried away, and an out-feed velocity greater than the velocity of the loaded carrier base. These factors may be relatively adjusted tofeed out as much as is carried away or to control the rate of accumulation of surplus.

Since the rotor slips through the material as well as feeds material, it follows that the peripheral speed of the rotor is somewhat greater than the linear-speed of the out-fed layer.

In actual practice excellent results have been obtainedusing a mandrel and'apron so spaced as to form an out-feeding layer one and oneome a- 7 qflafiefmohes thick, to provide fills-varying i'rom one "and one haif :to two and one half I inches thick. "The velocities-are regulated to provide a bump as desci 'ibe'dbut to minimize accumulation and excessive igrowth ofthe hump.

"In operation as described with reference to Fig. 1, the"-hopper is'rnaintained well smashed with-'grantilar material 1 0, such-as a mixture of coniniinnted wood, ere'ferably sawdust, and a thermosettl-ngresin powder. The-latter maybe used in proportion-from t'o fl'ii-pa-rt's icy"weight to 1 01) om ts of wood (oven-dry basis). The moisture contentofthesawdust or-mistureshould :be hiniorm for uniformity of panels, but it may vary over a wide range, preferably oeing-dry at around-% to '%-oy weight. Higher and lower moisture contents are permissible. The die-- tancebetween the mandreli 0 and the top o'f ed'ge 1 5- is' l'e'ss thanthe=disttrnce from the top of sheet $0 to-theiundeis'ide ofthe hopper. Rotorfl-il feeds material Wont of the hopper along I its floor I 4 and enerally horizontallyasshownat H 61f the straight-edge l t. Thespeedof ro'tor -zo'mo'ves' the material out -of--the hopper as a layer 'or stream 1 moving ata velocitygreatenthan the velooity of the sheet so, on relative to the hopper, whereby: the stream at =='H acts as a kinetic doctor-to level the'load Il -"already *deposited. The teeth 22 break and loosen the material sownere it may tendi to oeke' in the hopper and that which is fed ouvis'loosene'dand oi-constantdensity, of course where'thecharaoter of the mixture remains constem. Tne's'trwm at?! moves as a-gr'anular mass and then falls or moves by gravity without fractionation. Preferably, more material is fed out by ine rotor than is taken-away as load i2. The result is to form a-gr'owing hump 13 of excess mateiial to and under which the bare carrier sheetmoves as it is loaded by the hump. Then the-kinetic-doctor I I levelsoff the load as itpasses under the hopper bottom. The speed of the rotor may be regulated so as to minimize-or even prevent th'e accumulation of excess, but it is preierably dperated sothat the hump grows only slighnyas arr-assurance against some temporary reduction inf-the out-feed. Numeral 16 (=Figs. l and 2) -represerits control means to :rotate' tne rotor l e and means to move the carrier base so In fitnel fel'ation tothe speed of -the rotor, the "Controls bi ngindioated byfiottefii linesfl andi a, an fo'r the reasons and purposes described.

when spaced trays --are :used, one "passing :of the trafling trayend lets theimaterial oi'inump 7% fall in'to hopper 3S. To initiate the' ill-ling oi a has, its leading end is arrested at the loa din'g 'zoHeuntil-a-sizeable hump is is aormedpand then thetray is allowed to =move=in timed r'e'lation to th'e speed oi' the rotor 'l=9 so that the hump is m:iin'talne"d, and preferably gi'ows iorassnronce. The excess matefial in'tl-i'elnimp $3 is areserve -supply in theevent of an air pocket or-other mequality of "out-feed over straight edge 15.

where is continuously moving. endless :oarnier base 30 1's :used, ithe size 'of the :hump "Bf-may r oontinuousl-y loadmg and continuously mov The latter 8 mg" as-used herein and in the -=c1a'ims compre' hend *the action taking place between the eta-rt ingand stopp'i-ng of the base beingloaded, whether it be-an endless carrier base or an elongated rigidtray, as shownand described. Inasmuch as 'thereis a controlled relation between the velocity "of the'carrier base in one direction and the velocity of the out-fed stream in the opposite direction, continuous motion at such related velocities isi-n order, as against, for example-a series of short advances and momentary halts.

From the foregoingit will be appreciated that various changes and modifications may ice-made without departing from the spirit and scope-of the invention as expressed in the appended claims.

I claim:

-1. 'Theme'thod ofjcontinuously loading a'moving-c'arrier base'to a predetermined height with granular materialwhioh comprises continuously moving. auni'forn'ily-thick layer of granular mat'erial'at a feeding velocity in a generally horizontal direction from a region above a fixed horizontal plane, continuously moving a carrier base to beloa'ded in'sald plane at a lower velocity in a direction opposed to the moving material whereby the fedcmaterial gravitates 'as a mass to said base, the distancefrom said plane-tothe bottom or said layer being predeterm'inedly greater than the thickness of said layer, and

relating the feeding'v'lo'city of "said layer to "the velocity of movement of said base "so as to form and maintain a ridge of'material on the'movin'g base at least as high'asthe bottom of said layer, whereby the "force of the moving material at the bottom of said layer functions mechanically as a doctor to level the material being carried away from said ridge by said carrier base, the said greater distance 'being such that the resulting doctored'fill carried away on said "base has"thickne'ss in the range from at least as thick as to "thicker than the thickness of the said layer.

2. "The methodzof continuously loading amoving carrier base to a predetermined height with granular ma-teriahwhich comprises maintaining a' supply of "such material, continuously moving a uniformly "thick layer .of granular material at a feeding velocity in "a generally horizontal direlation-from th'e'bottom of 'said supply at a region above a fixed'horizontaLplane, continuously'moving acari'ier base'to be loaded in said plane at a lower velocity in a direction opposed .to the moving matei'lal'whereby the fed material gravitates as a mass to said base, the distanceirom saidp'lane to the bottom of said layer being predeterminedly :greater than the thickness of said layer, and relating the feeding velocity of saidlayertoithavelocityiof movement of saidl'base so asto form and rmantain a ridge of material onth'emovingbase .atle'ast as high as the bottom o'fsaidla'yer, "whereby the force of the moving materialatthe f'b'ottom of saidlayer functions mechanically 'as. a doctor to level the material being carried away from said ridgebysaid carrier "base, .the said greater distance being such that the resulting doctored fill carried away on saidbase has a thickness in the range from a'tleast as'th'ick as to thicker than the thickness of the said layer.

v.3. Themet'hod of continuously loadinga moving carrier-base. tola predetermined height with granular material which comprises continuously moving aiuniiormlylthick'layer of granular material .atea feeding velocity in agenerally horizontal direction fromia region above a fixed horizontal plane, continuously moving a carrier base to be loaded in said plane at a lower velocity in a direction opposed to the moving material whereby the fed material gravitates as a mass to said base, the distance from said plane to the bottom of said layer being predeterminedly greater than the thickness of said layer, relating the feeding velocity of said layer to the velocity of movement of said base so as to form and maintain a ridge of material on the moving base at least as high as the bottom of said layer, whereby the force of the moving material at the bottom of said layer functions mechanically as a doctor to level the material being carried away from said ridge by said carrier base, the said greater distance being such that the resulting doctored fill carried away on said base has a thickness in the range from at least as thick as 'to thicker than the thickness of said layer, said carrier base being flexible and subject to deviation from a, plane, planarizing the base carrying the resulting load, and skimming off to -a plane face the topmost particles of the load I over the planarized base.

4. The method of continuously loading a moving carrier base to a predetermined height with granular material which comprises maintaining a supply of such material, continuously moving a uniformly thick layer of granular material at a feeding velocity in a generally horizontal direction from the bottom of said supply at a region above a fixed horizontal plane, continuously moving a carrier base to be loaded in said plane at a lower velocity in a direction opposed to the chanically as a doctor to level the material being carried away from said ridge by said carrier base, the said greater distance being such that the resulting doctored fill carried away on said base has a thickness in the range from at least as thick as to thicker than the thickness of the said layer, said carrier base being flexible and subject to deviation from a plane, planarizing the base carrying the resulting load, and skimming off to a plane face the topmost particles of the load over the planarized base.

5. The method of continuously loading a moving carrier base to a predetermined height with granular material which comprises continuously moving a uniformly thick layer of granular material at a feeding velocity in a generally horizontal direction from a region above a fixed horizontal plane, continuously moving a carrier base to be loaded in said plane at a lower velocity in a direction opposed to the moving material whereby the fed material gravitates as a mass to said base, the distance from said plane to the bottom of said layer being predeterminedly greater than the thickness of said layer, relating the feeding velocity of said layer to the velocity of movement of said base to form and maintain a ridge of material on the moving base at least as high as the bottom of said layer, whereby the force of the moving material at the bottom of said layer functions mechanically as said layer, whereby the force of the moving material at the bottom of said layer functions mea doctor to level the material being carried away from said ridge by said carrier base, the said greater distance being such that the resulting doctored fill carried away on said base has a thickness in the range from at least as thick as to thicker than the thickness of said layer, said carrier base being flexible and subject to deviation from a plane, and planarizing the carrier base at the region of said doctoring, whereby the doctored level is parallel to the planarized base at a predetermined height thereon.

6. The method of continuously loading a moving carrier base to a predetermined height with granular material which comprises maintaining a supply of such material, continuously moving a uniformly thick layer of granular material at a feeding velocity in a generally horizontal direction from the bottom of said supply at a region above a fixed horizontal plane, continuously moving a carrier base to be loaded in said plane at a lower velocity in a direction opposed to the moving material whereby the fed material gravitates as amass to said base, the distance from said plane to the bottom of said layer being predeterminedly greater than the thickness of said layer, relating the feeding velocity of said layer to the velocity of movement of said base to form and maintain a ridge of material on the moving base at least as high as the bottom of the said layer, whereby the force of the moving material at the bottom of said layer functions mechanically as a doctor to level the material being carried away from said ridge by said carrier base, the said greater distance being such that the resulting doctored fill carried away on said base has a thickness in the range from at least as thick as to thicker than the thickness of said layer, said carrier base being flexible and subject to deviation from a plane, and planarizing the carrier base at the region of said doctoring, whereby the doctored level is parallel .to the planarized base at a predetermined height 1 thereon.

7. Apparatus comprising a hopper having a lateral opening at the bottom of its front wall,

said opening being defined at the bottom by a straight edge at the bottom of the hopper, a horizontal cylindrical rotor mounted in said opening with its face close to said straight edge,

said rotor having an inner mandrel and spaced jteeth projecting from said mandrel, thev ends of said teeth defining the cylindrical face of the rotor, means to turn the rotor to feed material at a feeding velocity out of the hopper .as a

layer in a substantially horizontal direction off said straight edge, means providing a support for moving a carrier base at a level spaced be- ,low said hopper and horizontally in a direction opposed to material fed from the hopper by the rotor, and means to move said carrier base at a lower velocity whereby to form and maintain a ridge of out-fed material on said base forward of the hopper, whereby said base carries a depth of fill away from said ridge, the distance from said mandrel above the edge of the bottom opening being such as to provide an out-feeding layer thinner than the depth of said fill, whereby the force of moving material in the bottom of said out-feeding layer functions mechanically to doctor the fill to a uniform level.

8. Apparatus comprising a hopper having a lateral opening at the bottom of its front wall, said opening being defined at the bottom by a straight edge at the bottom of the hopper, a horizontal cylindrical rotor mounted in said open- 11 log. with its face close to: said straight edge, said rotor havingam inner mandrel and. spaced teeth projecting from. saidmandrel, the endsot said teeth defining the cylindrical face ofv the rotor, means to turn the rotor taieed' materialat a feeding velocity out of, the hopper as alayer in a substantially horizontal direction-off said straight edge, means providing support for moving a magnetic sheet carrier base. at a, level spaced below said hopper and horizontally ina directionopposed to material fed: from the hopper .by the rotor, magnetic means arranged, to provide a. planarizing platform. at said, level and under the hopper for a said magnetic sheet carrier base, and, meanato-move said carrier base at a lower velocity whereby to form and main- .tain a ridge of out-fed. material on said-.ba-sefor.- ,ward :of the. hopper, vii-hereby said, base. carries a depth of fill away from said; ridge,.the distance from, said mandrel. above the. edge of the. bottom opening beingsuch as to provide an out-feeding layer thinner. than the depthof. saidfill, whereby the. force oil movingmaterial in the bottom of said outefeeding. layerfunctions: mechanically to doctor the fillto-a-uniiorm level.

9. Apparatus for filling, a sequence of trays comprising, a hopper havingalateral opening at. the bottom of itsfront wall, said; opening beingdefined at the. bottom by, a straight edgeat the bottom of the hopper,ahorizontalcylindnical rotormounted in saidopening. with its face close to said straight. edge, said rotor having an inner mandrehandx spaced teeth projecting. from said mandreh the. endsv of said. teeth. defining the. cyl-i'ndrical face oi the rotor, means. to tur11.tl1erotor to .feed material at aieeding velocity out of the hopper. as: a. layer in .a. substantially horizontaldirection ofE said straight edge, means pro.-

viding asupport for. moving; atray at a. level spaced .below said. hopper and horizontally in. a direction opposed to. material. fed from the hop perby the rotor, means to move. said; tray at a lower velocity whereby to form and maintain a ridge ofv out-fed material. on saidtray forward of the. hopper, whereby said. tray carries a depth of fill. away from. said ridge, the distance fi om said mandrel above the edgeof the bottom opening being such as. to provide an out-feeding. layer thinner than the depth .ofsaid fill, whereby the forceof'movi'ng material in. the bottomof said out-feeding layer, functions mechanicallyto doot'or the fill to a. uniform level,and a hopper below saidlevel. opening under the location ofisaid; ridge to receive the mat'eriaIoffthe ridge on passage ofalone tray under the hopper.

1'0. Apparatus for filling, a. sequence. of trays having a magnetic:sheetv bottom, comprising, .a hopper havinga lateral opening atithebottom 0t its from: wall, said. opening ,b'eing defined. at

, ta1ly=in a direction opposed to. material fed from the hopper by the rotor, spaced magnetic means arranged to providea planarizing plat form at said level and under the hopper for the magnetic bottom of a tray, means to move such a tray at. lower velocitywhereby to formand maintain.- a. ridge ct out-fed material. onsaid tray forward of the hopper, whereby: said traycarriesla depthioi fill awayfrom said, ridge,..the distance from. saidzlmandrel above theedge of the bottom openingbeing such asto: provide-an out-feeding, layer thinner than the depth oi said fill, whereby the force or"- moving material. in

the bottom of said out-feeding layer functions mechanically to doctor the fillta aun-iflormilevel, and. a hopper below said level opening under the. location of said ridge to, receive. the mate.- rial of the ridge on passage.- of a lone tray under the hopper, the opening; of the. hopper containing saidspa'ced.magneticmeans.

11. The method. of loading a moving carrier to adoctored level with,fiowablematerial which comprises moving, the carrier horizontally incnc directiomieeding, over. andbnto, the. carrier in a substantially horizontal directionarelatively thinlayer of the ,materialzat a-velocityinthe feeding direction greater than. the velocity of the carrier in. theopposite direction, the location of the.,carrier belowsaid feeding layer be.- ing such as. tocarry material away in quantity varying, in the rangef'rom less thanntoasmuch as the quantity of' materialbeing, fed as said layer, whereby the bottom or saidlayer functions as ainechanical doctor to level the material carried away by said carrier,,and anyexcessof-Lfeed material accumulates on said. carrier aheadof the out-feeding, layer.

FREDERICK WEYERHAEUSEE.

References-Cited in the file ofv this patent UNITED STATES, PATENTS Number: Name: Date 1 902,178: Sheehan Oct. 27, 19.08 1,807,475 Whitest. 31 Feb; 17; 1914 2,579,527 Weycrhaeuser Dec; 25; I951 

